Tanks filled with liquid carbon dioxide are used for a wide variety of purposes. One of the principal uses of a tank of liquid carbon dioxide is to introduce carbon dioxide into a soft drink to create an effervescent drink. A typical use is in a soda fountain type function or in a vending machine where water, syrup, and carbon dioxide are mixed to produce a soft drink. Inasmuch as tanks of this general type are expensive, it is necessary to refill the tanks with liquid carbon dioxide once the tank is empty. It is particularly desirable to provide an apparatus for receiving empty tanks, filling the tanks with liquid carbon dioxide, and delivering filled tanks.